An arrangement of the above-stated type is known for example from publication WO 2010/094539 A1. To secure a functional position of a shroud plate of a rotor of a gas turbine, which shroud plate is arranged on an outer circumference of a rotor disc of the rotor, relative to a moving blade of the rotor arranged on the outer circumference of the rotor disc, said publication proposes inserting a locking element into an opening formed in the manner of keyhole in the shroud plate, which locking element engages in its functional position in a hole arranged on a side, facing the shroud plate, of a blade root of the moving blade. This functional position of the locking element is secured in that, in a given rotational position relative to the shroud plate, the locking element engages behind the edge of the opening on the blade root side by means of a cam formed on the locking element and in that the locking element located in this rotational position is secured against rotation relative to the shroud plate about a longitudinal axis of the locking element. Securing of the rotational position of the locking element is achieved in that part of the locking element is deformed plastically and thereby engages in a bit opening of the keyhole-like opening.